Study On Influencing Factors Of Thin-walled Workpiece's Surface Quality During Peripheral Milling

Thin-walled workpiece is mentioned lightweight structural workpiece, which is composed of thin boards and strengthening rib and increasingly important application. But it is very difficult to manufacture thin-walled workpiece due to deformation, destabilization and vibration, which arise the attention of the world.High-speed cutting is an increasingly developed high and new technology in manufacturing in the world nowadays. In the industry developed country, high-speed cutting is recognized as a new cutting machining conception by more and more mechanical engineers. Compared with other processing methods in cutting thin-walled workpiece with low stiffness, high-speed processing has obvious advantages. Because there are the characteristics of small cutting force, low cutting thermal deformation, high cutting speed, high material removal rate, high machining precision and so on. A mass of cutting heat go with high-speed chip, even in no-cooling condition; the thermal distortion and compressive distortion of work piece and cutter are slight. We can get not only high cutting efficiency, but also high cutting precision. While machining long and low rigidity thin-walled work piece, we can also acquire satisfied machining effect.Chatter is a self-excited vibration that can occur during machining operations. This undesirable phenomenon is one of the most common limitations when it comes to improving productivity and part quality. For this reason, several methods have been developed with the aim of preventing, avoiding, reducing, suppressing or controlling the occurrence of chatter. A stability lobes diagram (SLD) shows the boundary between chatter-free machining operations and unstable processes, in terms of axial depth of cut as a function of spindle speed. These diagrams are used to select chatter-free combinations of machining parameters.In this paper, the machining processes of thin-walled work piece by the high-speed milling are investigated and the method of modeling and simulation of cutting force is presented. The cutting force in helical milling are modeled based on a predictive machining theory, in which the machining characteristic factors are predicted from input data of fundamental work piece material properties, tool geometry and cutting conditions. In the model, each tooth of a helical milling cutter is discredited into a number of slices along the cutter axis to account for the helix angle effect on the cutting forces. The cutting action of each of the slices is modeled as an oblique cutting process. The total forces acting on the cutter is obtained as the sun of the forces at all the cutting slices of all the teeth. A Matlab-based simulation system for the cutting forces in helical milling is developed using the model, which is proven to be a feasible and practical by the milling test.Secondly, a experiment method for stability lobes diagram is presented. It is easy to get FRF between spindle and cutter by impact test. And the function is modeled and investigated further. The milling dynamics force is modeled again. The simulation results show that the cutting force affect surface quality and suggest how to select cutter and milling parameters for the ideal cutting force distribution.Finally, after high-speed milling thin-walled work piece orthogonal test and measure test, an influence law is presented how milling parameters affect dimensional accuracy, surface quality and roughness. So it is easy to get a optimization milling parameters for the production.All the models, prediction of cutting force, chatter stability analysis, prediction of surface quality and roughness, are proven well by experimental results of three tests in this paper.